Master of Science / Department of Geology / Charles G. Oviatt / The Dyer Mountain quadrangle, located in Utah approximately 200 km east of Salt Lake City and 20 km north of Vernal, lies on the south flank of the east-west trending Uinta anticline. The topography of the area varies from mountain peaks to deep canyons, with rolling hills of uplands in between. The elevation in the quadrangle ranges from 3124 m (10248 ft) at the top of Dyer Mountain to 1835 m (6020 ft) at the lowest point of Big Brush Creek. Most of the northern portion of the quadrangle is vegetated by aspens and pines, whereas the southern part of the quadrangle is covered with sagebrush and grasses. Due to its location on the anticline, the quadrangle contains bedrock that dips gently to the south and southeast. The ages of the rocks within the quadrangle range from the Precambrian Uinta Mountain Group to the Quaternary and Tertiary gravels. Also present are the following formations: Cambrian Lodore; Mississippian Madison, Doughnut, and Humbug; Pennsylvanian Round Valley and Morgan; Pennsylvanian to Permian Weber; Permian Meade Peak Member of the Phosphoria and Franson Member of the Park City; and various Quaternary sediments. The Lodore Formation and the Madison Limestone rest on major unconformities, and the Quaternary and Tertiary gravels overlie the Gilbert Peak erosion surface. The Uinta anticline and southerly dip of the Proterozoic and Paleozoic rocks are a result of Late Cretaceous uplift during the Laramide orogeny; Tertiary rocks within the area show little to no deformation. Limestone and various types of ores have been mined in the quadrangle, and phosphorous is currently being mined for fertilizer production. Several landslides, common at the juncture of the Quaternary and Tertiary gravels and Permian shales, were identified within the quadrangle. An anticline and syncline, trending northwest to southeast, lie in the southeast portion of the quadrangle and transect Big Brush Gorge. Geologic hazards of the area include landslides, erosion and failure of road grades, and cliffs near trails. The karst topography of the area presents dangers of sink holes, and evidence of ceiling collapse is present within Big Brush Cave, a popular destination for tourists and cavers.

I present physical shear-box experiments investigating the relationship between geometrical properties of shear zones and mechanical properties of deformed rocks. Experimental methodology is also examined critically and new materials for analogue modelling of shear localization are presented. First, I tested experimentally whether meaningful rheological information can be deduced from finite geometrical shear zone data. The results predict characteristic geometrical responses for certain end-member materials. However, it will be difficult to constrain such responses in the field. In the second part physical controls on deformation in the shear box are analysed for Newtonian and power-law fluids and an elastoviscoplastic strain-softening material. Since models always represent simplifications of the natural problem, it is essential to understand fully the physics of a given simulation. I show that displacement boundary conditions, model geometry, and rheology control shear zone geometry. Practical applications of the shear box for modelling natural shear localization and limitations of isothermal physical models with displacement boundary conditions in general are discussed. In the third part, new data on the rheology of highly-filled silicone polymers are introduced. Since dynamic similarity must be satisfied in analogue models to permit scaled, quantitative simulations of deformation processes, the choice of suitable rock analogues is critical for physical experiments. In particular, we address the problem of designing power-law fluids to model rocks deforming by dislocation creep. We found that highly-filled polymers have complex rheologies. Hence, such materials must be used with care in analogue modelling and only for certain experimental stress-strain rate conditions. Finally, I investigated whether fault network geometry and topography of brittle strike-slip faults are influenced by the degree of compaction of the host rock. Analogue shear experiments with loose and dense sand imply that the degree of sediment compaction may be a governing factor in the evolution of fault network structure and topography along strike-slip faults in sedimentary basins. Therefore, models of strike-slip faults should consider potential volume changes of deformed rocks.

Master of Science / Department of Geology / Matthew W. Totten / 3D seismic surveys have become the backbone of many exploration programs because of their high resolution and subsequent success for wildcat test wells. There are occasions when the predicted subsurface geology does not agree with the actual geology encountered in the drilled well. A case in point occurred during the drilling of several wells based upon a 3D seismic survey in Ness County, Kansas, where the predicted Cherokee Sand did not meet the expectations. By better understanding the subsurface geologic features in the subject area, this study will attempt to answer the question “what went wrong?” Seismic attribute analysis workflow was carried out and the results were correlated to the available geological and borehole data within the survey boundaries. The objective of running this workflow was to describe facies variations within the Cherokee Sandstone. Correlations between seismic attributes and physical properties from well data were used to define these variations. Finally, Distributions of the seismic facies were mapped to predict the distribution of potential reservoir rocks within the prospect area.

Master of Science / Department of Geology / Matthew W. Totten / The Spivey-Grabs-Basil oil field is a highly developed field in south-central Kansas, having large variability in its production and in the Pineville Tripolite facies. The Pineville Tripolite is the primary producing formation of this field having major isopach variations, possibly influencing production. The hypothesis that the field is highly compartmentalized is from the varied production, isopach and structure of the field. This study investigated the Pineville Tripolite facies in the Spivey-Grabs-Basil Oil Field, with the Basil area the predominant focus, and its possible compartmentalization by looking at the gas chromatograms and their biomarker signatures. This field has had several studies investigating the geophysical attributes, depositional setting and large-scale compartmentalization. Post depositional sea-level changes and possibly syntectonics exposed the Reeds Spring to a sub-aerial environment where meteoric alteration created immense porosity and the Pineville Tripolite facies. Geochemical data shows evidence that this section of the field is sourced from both a marine shale and carbonate source at peak oil maturity, deposited in an anoxic environment. Biodegradation appears very slight, with most alterations transpiring in the alkane ranges only, leaving all other susceptible hydrocarbons unaltered. Compartments within the field are harder to identify when comparing geological data to oil data. Isopach data shows altered thickness of the Pineville Tripolite from well to well, as do Pineville structure values. The isopach and structural data point to possible areas for compartments, but it is from oil geochemical data that compartments become more visible. API gravities and GOR show motley values, but do indicate two significant areas of segregation. The deepest, most southern end of the study showed lighter gravity oils than the middle, suggesting possible fill and spill between the two. However, biomarker abundance indicates three possible compartments. The southern compartment has many more biomarker volumes than do the middle compartment, both divided by a reservoir pinch-out. The third most northeastern well has high biomarker abundance, but shows no geological separators from the other wells. Production from this field may be improved by investigating the biomarkers to allocate these compartments and possible barriers close to wells.

In contrast to early work establishing the importance of earthquake-induced liquefaction in producing soft-sediment deformation (SSD) of the Navajo Sandstone, this report advances the use of SSD analysis to: characterize wet climatic conditions and flood events during the depositional history of ancient eolianites; discriminate the signatures of multiple deformation events from those of complex deformation features formed in a single event; and to document the occurrence of liquefaction features unrepresented in modern Earth analogues. The diversity of deformation styles, presented here, is very unusual in a report from a single formation; yet the high resolution of interpreted time relationships between various processes of deposition, erosion, water table fluctuation, and deformation is even more notable. These exceptional features derive from the extraordinary outcrops of the Colorado Plateau, which expose many large-scale (tens of meters) features throughout their entire extent and reveal an extended history of episodic deformation through thick (hundreds of meters) sections of cross-bedded units, which frequently continue along several kilometers of cliff face. Prior studies of fluid escape from unconsolidated sand that support the present work are outlined in Chapter II. These include laboratory simulations of liquefaction and fluidization as well as analyses of analogous deposits, both ancient and modern. Chapter III provides an overview of outcrop evidence, gathered during the course of this study, for dramatic alterations in the topography and sedimentation patterns of the Navajo erg. Interpreted perturbations include: the foundering of active dunes; sediment eruptions; and the subsidence of interdune surfaces. Chapter IV constitutes an example of the detailed analyses that support the overview of Chapter III. Outcrop features from a site in West Canyon, Arizona provide the basis for interpreting the subsidence of a dry interdune surface to a position several meters below the contemporary water table, followed by the filling of this depression with a succession of mass flow, lacustrine, and eolian deposits. Chapter V outlines the implications of various outcrop features for the prevailing model of soft-sediment deformation in the Navajo Sandstone. Proposed modifications of this model accommodate a broader range of deformation dynamics and specifically incorporate the impact of wet climates.

In contrast to early work establishing the importance of earthquake-induced liquefaction in producing soft-sediment deformation (SSD) of the Navajo Sandstone, this report advances the use of SSD analysis to: characterize wet climatic conditions and flood events during the depositional history of ancient eolianites; discriminate the signatures of multiple deformation events from those of complex deformation features formed in a single event; and to document the occurrence of liquefaction features unrepresented in modern Earth analogues. The diversity of deformation styles, presented here, is very unusual in a report from a single formation; yet the high resolution of interpreted time relationships between various processes of deposition, erosion, water table fluctuation, and deformation is even more notable. These exceptional features derive from the extraordinary outcrops of the Colorado Plateau, which expose many large-scale (tens of meters) features throughout their entire extent and reveal an extended history of episodic deformation through thick (hundreds of meters) sections of cross-bedded units, which frequently continue along several kilometers of cliff face. Prior studies of fluid escape from unconsolidated sand that support the present work are outlined in Chapter II. These include laboratory simulations of liquefaction and fluidization as well as analyses of analogous deposits, both ancient and modern. Chapter III provides an overview of outcrop evidence, gathered during the course of this study, for dramatic alterations in the topography and sedimentation patterns of the Navajo erg. Interpreted perturbations include: the foundering of active dunes; sediment eruptions; and the subsidence of interdune surfaces. Chapter IV constitutes an example of the detailed analyses that support the overview of Chapter III. Outcrop features from a site in West Canyon, Arizona provide the basis for interpreting the subsidence of a dry interdune surface to a position several meters below the contemporary water table, followed by the filling of this depression with a succession of mass flow, lacustrine, and eolian deposits. Chapter V outlines the implications of various outcrop features for the prevailing model of soft-sediment deformation in the Navajo Sandstone. Proposed modifications of this model accommodate a broader range of deformation dynamics and specifically incorporate the impact of wet climates.

The purpose of this project was to determine the vanadium bearing ore minerals present at the Green Giant vanadium-graphite deposit in the S.W. of Madagascar owned by Toronto based Energizer Resources Inc. The rocks are mainly quartzofeldspathic gneiss, with alternating bands of hornblende biotite gneiss, marble, granitoid, and amphibolite. Using X-ray diffraction, electron microprobe analysis, and Raman spectroscopy, the vanadium bearing minerals were identified as vanadium bearing rutile, schreyerite, berdesinskiite, karelianite, a member of the karelianite-eskolaite solid solution, V-bearing phlogopite, V-bearing pyrrhotite, V-bearing pyrite, goldmanite, dravite, uvite, actinolite, and unidentified V-sulphide 1, V-sulphide 2, and V-silicate 1. The mineral assemblage present at Green Giant deposit is quite similar to that at Lake Baikal, Russia. Vanadium-bearing phlogopite is primary vanadium host in the deposit, although V-bearing oxides contribute substantially to the total V concentration, even where present in very trace amounts.

The purpose of this project was to determine the vanadium bearing ore minerals present at the Green Giant vanadium-graphite deposit in the S.W. of Madagascar owned by Toronto based Energizer Resources Inc. The rocks are mainly quartzofeldspathic gneiss, with alternating bands of hornblende biotite gneiss, marble, granitoid, and amphibolite. Using X-ray diffraction, electron microprobe analysis, and Raman spectroscopy, the vanadium bearing minerals were identified as vanadium bearing rutile, schreyerite, berdesinskiite, karelianite, a member of the karelianite-eskolaite solid solution, V-bearing phlogopite, V-bearing pyrrhotite, V-bearing pyrite, goldmanite, dravite, uvite, actinolite, and unidentified V-sulphide 1, V-sulphide 2, and V-silicate 1. The mineral assemblage present at Green Giant deposit is quite similar to that at Lake Baikal, Russia. Vanadium-bearing phlogopite is primary vanadium host in the deposit, although V-bearing oxides contribute substantially to the total V concentration, even where present in very trace amounts.

This thesis investigates the timing and mechanisms involved in the formation of evaporite piercement structures on Ellef Ringnes Island, Canadian Arctic Archipelago. The study includes the interpretation of industry seismic reflection and borehole data to characterize the geometry of the domes, 1D backstripping of wells to investigate the role of tectonic influences on diapirism, and analogue modelling to better understand the mechanisms that drive diapirs with dense anhydrite caps. I propose that basement structures played a significant role in the formation of evaporite domes by triggering and directing salt movement. The domes developed during the Mesozoic by passive growth driven by the differential loading of salt on adjacent fault blocks, which led to their present day asymmetric geometries. Diapir growth rates in the Mesozoic were closely linked to the rate of sedimentation, which was greatly influenced by the amount of accommodation space provided by tectonic subsidence of the basin.

I present physical shear-box experiments investigating the relationship between geometrical properties of shear zones and mechanical properties of deformed rocks. Experimental methodology is also examined critically and new materials for analogue modelling of shear localization are presented. First, I tested experimentally whether meaningful rheological information can be deduced from finite geometrical shear zone data. The results predict characteristic geometrical responses for certain end-member materials. However, it will be difficult to constrain such responses in the field. In the second part physical controls on deformation in the shear box are analysed for Newtonian and power-law fluids and an elastoviscoplastic strain-softening material. Since models always represent simplifications of the natural problem, it is essential to understand fully the physics of a given simulation. I show that displacement boundary conditions, model geometry, and rheology control shear zone geometry. Practical applications of the shear box for modelling natural shear localization and limitations of isothermal physical models with displacement boundary conditions in general are discussed. In the third part, new data on the rheology of highly-filled silicone polymers are introduced. Since dynamic similarity must be satisfied in analogue models to permit scaled, quantitative simulations of deformation processes, the choice of suitable rock analogues is critical for physical experiments. In particular, we address the problem of designing power-law fluids to model rocks deforming by dislocation creep. We found that highly-filled polymers have complex rheologies. Hence, such materials must be used with care in analogue modelling and only for certain experimental stress-strain rate conditions. Finally, I investigated whether fault network geometry and topography of brittle strike-slip faults are influenced by the degree of compaction of the host rock. Analogue shear experiments with loose and dense sand imply that the degree of sediment compaction may be a governing factor in the evolution of fault network structure and topography along strike-slip faults in sedimentary basins. Therefore, models of strike-slip faults should consider potential volume changes of deformed rocks.